Rotary capacitor apparatus



Nov. 9, 1965 A. DOTTO ROTARY CAPACITOR APPARATUS Filed July 12, 1962 FIG-3 44 FIG-2 33 FIG-4 INTERNAL COMB US 7'/0N ENG/NE v Q a? m. w J

INVENTOR. GIANNI A. DOTTO ATTORNEY Uiiited States Patent C 3,217,216 ROTARY CAPACITOR APPARATUS Gianni A. Dotto, 3005 Ciaar Ave, Dayton, Ohio Filed July 12, 1962, Ser. No. 209,402 16 Claims. (Cl. 317-250) This invention relates to automotive apparatus. The invention relates more particularly to ignition control apparatus for an internal combustion engine. The ignition control apparatus utilizes a novel rotary capacitor apparatus which is the subject of the present invention.

It is an object of this invention to provide ignition control apparatus utilizing the novel rotary capacitor apparatus of the present invention by which higher efliciency operation of an internal combustion engine can .be obtained than is possible with any known ignition control system.

Another object of this invention is to provide ignition control apparatus utilizing the novel rotary capacitor apparatus of the present invention which provides consistent operation in the production of a high voltage, high current spark in a combustion chamber of an internal combustion engine during any speed or load in the engine operation.

Another object of this invention is to provide ignition control apparatus utilizing the novel rotary capacitor apparatus of the present invention which thus makes possible a very small amount of waste gases from the exhaust of the engine.

Another object of this invention is to provide ignition apparatus utilizing the novel rotary capacitor apparatus of the present invention which has a minimum number of moving parts and which has a minimum number of parts which are subject to wear or the like.

Another object of this invention is to provide such ignition apparatus utilizing the rotary capacitor apparatus of the present invention which can be produced at relatively low cost.

Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture, .and the mode of operation, as will become more apparent from the following description.

In the drawings:

IGURE 1 is a schematic diagram of ignition control apparatus utilizing the rotary capacitor apparatus of this invention.

FIGURE 2 is a sectional view of rotary capacitor a-pparatus of this invention.

FIGURE 3 is a sectional view taken substantially on line 3-3 of FIGURE 2.

FIGURE 4 is a fragmentary perspective view of a portion of rotary capacitor apparatus of this invention.

Referring to the drawings in detail, the apparatus of FIGURE 1 is illustrated as including a battery 16, which is ordinarily the conventional power supply battery of an automobile. The negative side of the battery 16 is shown as being grounded. The positive side of the battery 16 is connected by means of a conductor 18 to a resistor 20. An ignition switch 19 is shown in the conductor 18. The resistor 20 is connected in series with a capacitor 22 which is connected to ground. Thus, the series of the capacitor 22 and the resistor 20 is connected across the battery 16.

Also, connected to the conductor 18 is a ballast resistor or impedance member 23 to which is series connected a primary winding 24 of an ignition coil or transformer 25. The ignition coil 25 may be a conventional ignition coil used in a present day ignition system. A diode 26 is shown as being connected to the primary winding 24.

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zones, usually four Zones, of alternate P and N material, there being a junction separating adjoining zones.

The controlled rectifier 28 has a cathode 29 at the end thereof opposite the anode 27. The cathode 29 -is connected to ground through an inductance element or impedance member or coil 30. The controlled rectifier 28 also has an intermediate junction or control electrode or gate 31. The controlled rectifier 28 is of the type which is ordinarily initiated into a conductive state by passing a given value of current through the gate 31. However, after conduction of current through the device is begun, the current continues to flow therethrough until the current decreases below a certain holding current value or until the voltage across the controlled rectifier is reversed.

Connected to the juncture between the resistor 20 and the capacitor 22 is a diode 32 which also is connected to the gate 31.

A rotary capacitor 33, discussed below, is connected by means of a conductor 34 to the anode 27 of the controlled rectifier 28. The rotary capacitor 33 is also connected to ground.

A capacitor 36 is shown connecting the primary winding 24 of the ignition coil or transformer 25 to ground. The capacitor 36 may be a capacitor used in a conventional ignition system.

The ignition coil 25 may be of a conventional type and has a secondary winding 37 which is shown as being joined to the primary winding 24 and to the capacitor 36. The primary winding 24 and the secondary winding 37 of the ignition coil or transformer 25 are wound on a common core. The secondary winding 37 connects through any suitable distributor mechanism 38 to a spark plug 39 or to any other suitable element having a desired spark gap within a combustion chamber of an internal combustion engine. The distributor mechanism 38 is further discussed below. The spark plug 39 is also connected to ground in a conventional manner.

The rotary capacitor The rotary capacitor, referred to by numeral 33, is shown structurally in FIGURES 2, 3, and 4. The rotary capacitor 33 is adapted to replace a conventional breaker point switch mechanism in a conventional ignition system. The rotary capacitor 33 ha a frame 40 which, by means of an insulating support member 42, supports an elongate annular member 44 which has a plurality of inwardly extending plates 46. The plates 46 are preferably arranged in equally spaced-apart stacks around the inner wall of the member 44, as shown in FIGURE 3. Each stack of plates 46 extends axially within the annular member 44. The plates 46 in each stack thereof are aligned and spaced-apart, as shown in FIGURE 4.

A rotary shaft 48, journalled within a bearing 50, rotatably supports a sleeve 52. Secured to the sleeve 52 and rotatable therewith is a hub 53 which carries a plurality of stacks of plates 54, so that there is one plate 54 movable between two plates 46 in each of the stacks thereof. The number of stacks of plates 46 and of plates 54 is shown as being equal. However, the number of stacks of plates 46 may be greater or smaller than the number of stacks of plates 54. Preferably, the number of stacks of plates 46 and the number of stacks of plates 54 is in a given ratio to the number of combustion chambers of the internal combustion engine with which the apparatus is associated. Ideally, the number of plates 46 is in a given even number ratio to the number of plates 54.

The shaft 48 is adapted to be attached to suitable mechanism of the engine for rotative movement therewith. Herein, the shaft 43 provides the ground connection of the rotary capacitor 33. However, connection may be made in any other suitable manner. The conductor 34 is connected to the annular member 44 and, as discussed above, is connected to the anode 27 of the silicon controlled rectifier 28.

A cover member 57 has at the upper portion thereof the distributor mechanism 38, mentioned above. An insulated carrier member 58 is attached to the shaft 48 for rotation therewith adjacent the upper portion of the cover member 57. The carrier member 58 supports a contact member 60 which resiliently engages a center stud 62. The contact member 60 also has a tip 64 which moves to closely spaced relationship with any on of a plurality of studs 66 to provide a circuit therewith. Each of the studs 66 connects to one of the cylinders of the engine for distribution of high voltage thereto from the secondary winding 37 of the ignition coil 25.

Also, attached to the shaft 48 is a conventional type of centrifugally operated mechanical advance mechanism 68 which rotates the hub 53 slightly with respect to the shaft 48 when a given speed of rotation of the shaft 48 is obtained. Connected to the annular member 44 is a rod '70 of a conventional type of vacuum advance mechanism 72. The conventional mechanical advance mechanism 68 and the conventional vacuum advance system 72 are of the type described and shown in US. Patent No. 2,131,019, issued to Arthur et al. on September 27, 1938.

When the ignition switch 19 is closed, current passes through the resistor or impedance member 20 and charges the capacitor 22. The time required for charging the capacitor 22 is, of course, determined by the values of the resistor 20 and the capacitor 22. After the capacitor 22 is charged to a predetermined degree, there is a fiow of current of a predetermined amount through the diode 32 and through the gate 31 of the controlled rectifier 28. This current flow causes the controlled rectifier to assume a conductive state and to conduct current therethrough. Thus, current fiows through the primary winding 24 of the ignition coil 25, through the diode 26, through the controlled rectifier 28, and through the inductance element or coil 30.

This flow of current begins when the rotary capacitor 33 has the rotary plates 54 thereof in the positions shown in FIGURE 3. However, with operation of the engine to which the shaft 48 of the rotary capacitor 33 is connected, the shaft 48 rotates and moves the stacks of plates 54 to positions within the stacks of plates 46, as shown in FIGURE 4. When such position of the plates 54 is obtained, the maximum capacitance of the rotary capacitor is obtained.

Preferably, the coil and the rotary capacitor 33 are constructed so that the inductive reactance of the coil 30 is equal to the capacitive reactance of the rotary capacitor 33. Therefore, as the plates 54 approach the positions thereof as shown in FIGURE 4, an oscillatory current of considerable value is established between the rotary capacitor 33 and the coil 30. As such oscillatory current is established between the coil 30 and the rotary capacitor 33, such oscillatory current flows through the controlled rectifier device 28.

As stated above, one method of stopping conduction of current through a controlled rectifier device, such as the device 28, is that of applying a reverse voltage across the device. Thus, within a cycle after the oscillatory current is established, a half cycle of voltage occurs across the controlled rectifier 28 which is opposite to the normal voltage thereacross. Such voltage in the reverse direction instantaneously cause the controlled rectifier device 28 to become nonconductive.

With the use of the diode 26 which is in series with the controlled rectifier 28 and which is connected to the capacitor 33, a greater voltage charge is created upon the capacitor 33 than would otherwise be possible. This is a result of the choke action of the winding 24 held by the diode 26. This causes a very rapid response of the tank circuit action of the capacitor 33 and the coil 30 to make the controlled rectifier 28 nonconductive when d the capacitor 33 approaches its maximum capacity position as shown in FIGURE 4.

As the circuit through the controlled rectifier 28 is instantaneously opened, there is a sudden collapse of the magnetic field in the core of the ignition coil 25 and a high voltage is induced in the secondary winding 37.

'"lhis high voltage in the secondary winding 37 causes a spark across the spark gap of the spark plug 39 which is connected to the secondary winding 37 through the distributor mechanism 38.

It is to be understood that the shaft 4-8 of the rotary capacitor 33 continuously rotates with operation of the engine to which the apparatus of this invention is associated. The shaft 48 of the rotary capacitor 33 continues to rotate and the plates 46 and 54 again appear as shown in FIGURE 3. The shaft 48 continues to rotate so that the plates 4-6 and 54 again appear in the manner shown in FIGURE 4 as the distributor mechanism 38 moves to initiate firing in another cylinder of the engine.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of plates carried by said hub means and extending radially therefrom at equally spaced-apart positions about said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said plates; a plurality of plates carried by said annular support member therewithin at equally spacedapart positions, said plurality of plates carried by said hub means having a given even number ratio to said plurality of plates carried by said annular support member, each of said plates carried by said hub means movable to a position adjacent in alignment with any one of said plurality of blades carried by said annular support member for establishing a capacitive relation therewith.

2. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of spacedapart plates attached to said hub means, said stacks of plates being equally spaced about said hub means and extending axially along said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; a housing encompassing said shaft and said hub means; a plurality of stacks of spaced-apart plates carried by said housing therewithin, said stacks of plates equally spaced about said hub means, each stack of plates extending axially along said hub means within said housing, each of said plates carried by said hub means movable to a position intermediate a pair of plates of said housing, each of said stacks of plates carried by said hub means movable to positions within any one of said stacks of plates carried by said housing.

3. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of plates attached to said hub means and extending radially therefrom at equally spaced positions about said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of said shaft is obtained; a plurality of plates fixedly positioned in equally spaced positions about said hub means, said number of fixedly positioned :3 plates equal in number to said number of plates attached to said hub means, each of said plates attached to said hub means disposed in axial alignment with and adjacent one of said fixedly positioned .plates.

4. In an ignition control apparatus for an internal combustion engine provided with a given number of combustion chambers; a rotary shaft, said rotary shaft coupled to and driven by an internal combustion engine, said internal combustion engine having a given number of combustion chambers; a rotary hub means carried by said shaft, said hub means including a plurality of plates extending therefrom at equally spaced-apart positions; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said hub means; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions; said number of plate positions of said plates carried by said annular support member being a given even number ratio to said number of combustion chambers of said engine, said number of plate positions of said plates carried by said hub means in a given even number ratio to said number of combustion chambers of said engine.

5. A capacitor comprising: a rotatable shaft; a rotatable hub means provided with a plurality of blades carried thereby and extending radially therefrom and equally spaced thereabout; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular member encompassing said hub means and said blades thereof, said annular member having an inner wall surface; a plurality of blades fixedly attached to said inner wall surface of said annular member, said number of blades attached to said annular member being in a given ratio to said number of blades carried by said hub means, each of said blades carried by said hub means movable thereby to a position adjacent any one of a plurality of said blades carried by said annular member.

6. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of plates carried by said hub means and extending radially therefrom at equally spaced-apart positions about said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said plates; a vacuum advance mechanism coupled to said annular support member for slightly rotating said annular support member with respect to said shaft when a predetermined vacuum is attained within said vacuum advance mechanism; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, said plurality of plates carried by said hub means having a given even number ratio to said plurality of plates carried by said annular support member, each of said plates carried by said hub means movable to a position adjacent in alignment with any one of said plurality of blades carried by said annular support member for establishing a capacitive relation therewith.

7. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of spacedapart plates attached to said hub means, said stacks of plates being equally spaced about said hub means and extending axially along said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; a housing encompassing said shaft and said hub means; a vacuum advance mechanism coupled to said housing for slightly rotating said housing with respect to said shaft when a predetermined vacuum is attained within said vacuum advance. mechanism; a plurality of stacks of spaced-apart plates carried by said housing therewithin, said stacks of plates equally spaced about said hub means, each stack of plates extending axially along said hub means Within said housing, each of said plates carried by said hub means movable to a position intermediate a pair of plates of said housing, each of said stacks of plates carried by said hub means movable to positions within any one of said stacks of plates carried by said housing.

8. A capacitor comprising: a rotary shaft; a rotary hub means carried by said shaft; a plurality of plates attached to said hub means and extending radially therefrom at equally spaced positions about said hub means; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of said shaft is obtained; a plurality of plates fixedly positioned in equally spaced positions about said hub means; a vacuum advance mechanism coupled to said plates about said hub means for slightly rotating said plates with respect to said shaft when a predetermined vacuum is attained within said vacuum advance mechanism; said number of fixedly positioned plates equal in number to said number of plates attached to said hub means, each of said plates attached to said hub means disposed in axial alignment with and adjacent one of said fixedly positioned plates.

9. In an ignition control apparatus for an internal combustion engine provided with a given number of combustion chambers: a rotary shaft, said rotary shaft coupled to and driven by an internal combustion engine, said internal combustion engine having a given number of combustion chambers; a rotary hub means carried by said shaft, said hub means including a plurality of plates extending therefrom at equally spaced-apart positions; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said hub means; a vacuum advance mechanism coupled to said housing for slightly rotating said annular support member with respect to said shaft when a predetermined vacuum is attained within said vacuum advance mechanism; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, said number of plate positions of said plates carried by said annular support member being a given even number ratio to said number of combustion chambers of said engine, said number of plate positions of said plates carried by said huh means in a given even number ratio to said number of combustion chambers of said engine.

It A capacitor comprising: a rotatable shaft; a rotatable hub means provided with a plurality of blades carried thereby and extending radially therefrom and equally spaced thereabout; a centrifugally operated mechanical advance means coupled to said shaft, said advance means for rotating said hub means slightly with respect to said shaft when a predetermined speed-of rotation of said shaft is obtained; an annular member encompassing said hub means and said blades thereof, said annular member having an inner wall surface; a vacuum advance mechanism coupled to said annular member for slightly rotating said annular member with respect to said shaft when a predetermined vacuum is attained within said vacuum advance mechanism; a plurality of blades fixedly attached to said inner wall surface of said annular member, said number of blades attached to said annular member being in a given ratio to said number of blades carried by said hub means, each of said blades carried by said hub means movable thereby to a position adjacent any one of a plurality of said blades carried by said annular member.

11. A capacitor comprising: a rotary shaft, said shaft coupled to and driven by an internal combustion engine; a rotary hub means carried by said shaft; a plurality of plates carried by said hub means and extending radially therefrom at equally spaced-apart positions about said hub means; a means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said plates; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, said plurality of plates carried by said hub means having a given even number ratio to said plurality of plates carried by said annular support member, each of said plates carried by said hub means movable to a position adjacent in alignment with any one of said plurality of blades carried by said annular support member for establishing a capacitive relation therewith.

12. A capacitor comprising: a rotary shaft, said shaft coupled to and driven by an internal combustion engine; a rotary hub means carried by said shaft; a plurality of spaced-apart plates attached to said hub means, said stacks of plates being equally spaced about said hub means and extending axially along said hub means; a means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; a housing encompassing said shaft and said hub means; a plurality of stacks of spaced-apart plates carried by said housing therewithin, said stacks of plates equally spaced about said hub means, each stack of plates extending axially along said hub means Within said housing, each of said plates carried by said hub means movable to a position intermediate a pair of plates of said housing, each of said stacks of plates carried by said hub means movable to positions within any one of said stacks of plates carried by said housing.

13. A capacitor comprising: a rotary shaft, said shaft coupled to and driven by an internal combustion engine, said internal combustion engine having a given number of combustion chambers; a rotary hub means carried by said shaft, said hub means including a plurality of plates extending therefrom at equally spaced apart positions; a means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said hub means; and a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, the number of plate. positions of said plates carried by said annular support member being a given even number ratio to said number of combustion chambers of said engine, the number of plate positions of said plates carried by said hub means in a given even number ratio to said number of combustion chambers of said engine.

14. A capacitor comprising: a rotary shaft, said shaft coupled and driven by an internal combustion engine; a rotary hub mean carried by said shaft; a plurality of plates carried by said hub means and extending radially therefrom at equally spaced-apart positions about said hub means; a mechanical means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; an annular support member encompassing said shaft and said plates; a vacuum means coupled to said annular support member for slightly rotationally advancing said annular support member with respect to said shaft when a predetermined vacuum is attained within said vacuum means; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, said plurality of plates carried by said hub means having a given even number ratio to said plurality of plates carried by said annular support member, each of said plates carried by said hub means movable to a position adjacent in alignment with any one of said plurality of blades carried by said annular support member for establishing a capacitive relation therewith.

15. A capacitor comprising: a rotary shaft, said shaft coupled to and driven by an internal combustion engine; a rotary hub means carried by said shaft; a plurality of spaced-apart plates attached to said hub means, said stacks of plates being equally spaced about said hub means and extending axially along said hub means; a mechanical means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained; a housing encompassing said shaft and said hub means; a vacuum means coupled to said housing for slightly rotationally advancing said housing with respect to said shaft when a predetermined vacuum is attained within said vacuum means; a plurality of stacks of spaced-apart plates carried by said housing therewithin, said stacks of plates equally spaced about said hub means, each stack of plates extending axially along said hub means within said housing, each of said plates carried by said hub means movable to a position intermediate a pair of plates of said housing, each of said stacks of plates carried by said hub means movable to positions within any one of said stacks of plates carried by said housing.

16. A capacitor comprising: a rotary shaft, said shaft coupled to and :driven by an internal combustion engine, said internal combustion engine having a given number of combustion chambers; a rotary hub means carried by said shaft, said hub means including a plurality of plates extending therefrom at equally spaced apart positions; a mechanical means coupled to said shaft, said means for rotationally advancing said hub means slightly with respect to said shaft when a predetermined speed of rotation of said shaft is obtained, an annular support member encompassing said shaft and said hub means; a vacuum means coupled to said housing for slightly rotationally advancing said annular support member with respect to said shaft when a predetermined vacuum is attained within said vacuum means; a plurality of plates carried by said annular support member therewithin at equally spaced-apart positions, the number of plate positions of said plates carried 'by said annular support member being a given even number ratio to said number of combustion chambers of said engine, the number of plate positions of said plates carried by said hub means in a given even number ratio to said number of combustion chambers of said engine.

References Qited by the Examiner UNITED STATES PATENTS 1,917,244 7/33 Edwards 317-253 X 2,477,635 9/49 Marchand 333-7 2,720,626 10/55 Wing 317-250 X 2,934,588 4/60 Ronci 174-50 2,938,095 5/60 Baskerville 200-164 2,966,570 12/60 Jordan 200-164 3,007,093 10/61 Potter et al 317-249 3,024,299 3/62 Nijhuis et al. 174-50 3,078,391 2/63 Bunodiere et al. 315-205 3,085,182 4/63 Napolin 317-249 3,087,090 4/63 Konopa 315-205 3,108,210 10/63 Pankove 317-235 3,114,867 12/63 Szekely 317-235 3,142,795 7/64 Greeley 200-24 FOREIGN PATENTS 448,144 10/49 Italy.

ROBERT K. SCHAEFER, Acting Primary Examiner.

GEORGE N. WESTBY, JOHN F. BURNS, LARAMIE E. ASKIN, Examiners. 

1. A CAPACITOR COMPRISING: A ROTARY SHAFT; A ROTARY HUB MEANS CARRIED BY SAID SHAFT; A PLURALITY OF PLATES CARRIED BY SAID HUB MEANS AND EXTENDING RADIALLY THEREFROM AT EQUALLY SPACED-APART POSITION ABOUT SAID HUB MEANS; A CENTRIFUGALLY OPERATED MECHANICAL ADVANCE MEANS COUPLED TO SAID SHAFT, SAID ADVANCE MEANS FOR ROTATING SAID HUB MEANS SLIGHTLY WITH RESPECT TO SAID SHAFT WHEN A PREDETERMINED SPEED OF ROTATION OF SAID SHAFT IS OBTAINED; AN ANNULAR SUPPORT MEMBER ENCOMPASSING SAID SHAFT AND SAID PLATES; A PLURALITY OF PLATES CARRIED BY SAID ANNULAR SUPPORT MEMBER THEREWITHIN AT EQUALLY SPACEDAPART POSITIONS, SAID PLURALITY OF PLATES CARRIED BY SAID HUB MEANS HAVING A GIVEN EVEN NUMBER RATIO TO SAID PLURALITY OF PLATES CARRIED BY SAID ANNULAR SUPPORT MEMBER, EACH OF SAID PLATES CARRIED BY SAID HUB MEANS MOVABLE TO A POSITION ADJACENT IN ALIGNMENT WITH ANY ONE OF SAID PLURALITY OF BLADES CARRIED BY SAID ANNULAR SUPPORT MEMBER FOR ESTABLISHING A CAPACITIVE RELATION THEREWITH. 